1. Technical Field
The present invention relates to a liquid crystal display apparatus employed in, for example, a television receiver and particularly, to a liquid crystal display apparatus for which a measure for preventing static electricity of a human body from exerting an adverse effect on a liquid crystal panel, a control circuit board, and the like has been taken by making a metallic edge frame member (called as “a bezel”) disposed around a liquid crystal panel electrically conductive to a metallic backboard member (called as “a rear frame”) disposed behind the liquid crystal panel.
2. Description of Related Art
As a liquid crystal display apparatus used in the camera field, a technique for connecting the unit to an earth of the unit body via a conductive member disposed under a liquid crystal display has been known (see JP-A-2003-84261, for example) Moreover, in the same camera field, sandwiching a liquid crystal display panel between a front case and a rear case and forming an earth contact by disposing, on both these cases, conductive end faces that are in contact with each other to form an earth contact (see JP-A-2000-19491, for example), and in a small-sized liquid crystal display apparatus employed in a car navigation system, disposing a metallic cover and a backside case on both sides of a liquid crystal module and making an earth terminal provided on the metallic cover into elastic contact with an earth contact provided on a face of a liquid crystal display circuit (see JP-A-2004-264342, for example) have been known. Furthermore, in the camera field, a technique for fitting a display window of a cover into the periphery of an LCD panel of an LCD assembly placed on an electric wiring board and making an earth piece of a spring structure contact with an earth surface so as to apply pressure for preventing electrostatic discharge damage has also be proposed (see JP-A-2004-252185, for example)
The above-related arts merely propose countermeasures against static electricity for small-sized liquid crystal display apparatuses used for cameras and navigation systems, therefore, such techniques cannot be directly applied to liquid crystal display apparatuses for television receivers that are often constructed in larger sizes than the same. Namely, in a liquid crystal display apparatus with a size of 15 inches or 20 inches used for a television receiver or the like, a liquid crystal panel constructed by a liquid crystal module cannot be directly sandwiched by a front case and a rear case. Namely, in the liquid crystal panel used for a television receiver, since it becomes necessary to secure an installation space of a light source being a backlight in the rear of the liquid crystal panel and provide a structure for reinforcing the liquid crystal panel, it becomes necessary to provide a frame useful for these in the rear of the liquid crystal panel. A related art of this type of liquid crystal display device will be described in the following with reference to FIG. 6.
FIG. 6 is schematic exploded perspective view of a main part of a liquid crystal display apparatus according to a related art. This liquid crystal display apparatus is disposed with, in a manner sandwiching a frame 1 made of a roughly rectangular loop-shaped resin molding, on both sides thereof, a metallic edge frame member (bezel) 6 that surrounds a liquid crystal panel 5 for a television receiver and sandwiches the liquid crystal panel 5 with the frame 1 and a backboard member (rear frame) 8 formed with a sheet metal thicker than the edge frame member 6, and on an outer surface side of the backboard member 8, a circuit board (unillustrated) used for, for example, driving the liquid crystal panel is mounted. And, the edge frame member 6 is fixed to the frame 1 by use of screws 3 at a plurality of points, and the backboard member 8 is likewise fixed to the frame 1 by use of unillustrated screws at a plurality of points. Also, in FIG. 6, reference numeral 9 denotes a relay board that is long sideways, and the relay board 9 is required for connecting the circuit board mounted on the backboard member 8 to electrodes of the liquid crystal panel 5, and is disposed along one side of the backboard member 8, specifically, an upper side portion.
In the liquid crystal display apparatus having the above construction, it has been known that, as a measure for preventing static electricity of a human body from jumping thereinto to exert an adverse effect on the liquid crystal panel 5, it is helpful to utilize the edge frame member 6 that fixes the liquid crystal panel 5 to the frame 1.
However, in an approximately 15-inch relatively small-sized liquid crystal display, electrodes (unillustrated) are positioned at an upper side portion of the liquid crystal panel 5, therefore, it is required to secure, at an upper side portion of the edge frame member 6, an installation space of a flexible wiring board (unillustrated) that connects the electrodes to the relay board 9. For this reason and others, as can be recognized in FIG. 6, the edge frame member 6 is screw-fitted to the frame 1 only at its left and right side portions. In contrast thereto, the backboard member 8 has mounting pieces 81 and 82 only at an upper side portion and a lower side portion thereof, in which a necessary mounting strength is secured by screw-fitting these mounting pieces 81 and 82 to the frame 1, no mounting pieces are provided at left and right side portions thereof to improve a material yield, whereby costs are reduced. Based on these facts, in order to collect static electricity of a human body at the edge frame member 6, release the same to the backboard member 8, and further release the same from the backboard member 8 to an earth pattern of the circuit board mounted thereon, it has been considered that an earth fitting 100 is inevitably required as extra.
The earth fitting 100 is formed by bending a sheet metal into a complex shape as in FIG. 7, one end portion thereof 110 is concurrently clamped onto the edge frame member 6 by use of one of the screws 3, and the other end portion 120 is joined to the backboard member 8 by means of a screw 4 as shown in FIG. 6.
In the liquid crystal display apparatus with this construction, the edge frame member 6 is useful for preventing, when static electricity of a human body has jumped into an installation site of said liquid crystal display device, exertion of an adverse effect on the liquid crystal panel 5 by conducting the static electricity. Namely, when static electricity of a human body has jumped into an installation site of said liquid crystal display apparatus, the static electricity flows through an AC power cord after being conducted to the edge frame member 6, earth fitting 100, backboard member 8, and circuit board in this order, and is released to the ground side.